The present invention relates to an electrical contact and a method for press-bonding [this] electrical contact to an electrical wire.
Electrical contacts having wire retaining barrels engage and maintain an electrical wire therein are generally known in the art. One example of such an electrical contact, which is disclosed in Japanese Utility Model Application Kokoku No. S45-33001, is shown in FIG. 7. This electrical contact 100 has a contact part 102 that electrically contacts a mating electrical contact (not shown in the figures), and a wire retention part 104 that is connected by bending the barrel around the outer circumference of an electrical wire (not shown in the figures). The wire retention part 104 is constructed from a pair of conductor barrels 104a, 104a which are bent about the core of the wire and frictionally engage the core wire, i.e., the conductor of the electrical wire. A pair of insulator barrels 104b, 104b are also provided and are bent about the outer covering of the wire and frictionally engage the outer covering, i.e., the insulation of the electrical wire. The conductor barrels 104a, 104a are formed so that their positions are offset relative to each other in the axial direction of the electrical contact 100. The insulator barrels 104b, 104b are also formed so that their positions are offset relative to each other in the axial direction of the electrical contact 100. The barrels are bent or press-bonded so that they envelop and frictionally engage the electrical wire from both sides of the electrical wire, thus pressing and fastening the outer covering of the electrical wire in place with the broadest possible area.
Furthermore, an electrical contact in which beveled surfaces are formed on the tip ends of the insulator barrels that are press-bonded or frictionally engaged to the outer covering of the electrical wire is disclosed in Japanese Utility Model Application Kokai No. S56-119264.
The barrel parts 104b, 104b of the electrical contact 100 disclosed in the above-mentioned Japanese Utility Model Application Kokoku No. S45-33001 are separated from each other in the axial direction of the electrical contact 100 after the barrels have been bent; accordingly, these barrel parts 104b, 104b are wrapped around the circumference of the outer covering of the electrical wire without contacting each other. As a result, the electrical contact 100 can be used on wires of various diameters, and the total length of the electrical contact 100 can be made relatively short. However, the pair of barrel parts 104b, 104b have no structural integrity following bending or press-bonding; consequently, the barrel parts 104b, 104b tend to open, so that the frictional engagement with the wire is weak, thereby allowing the wire to be inadvertently removed causing electrical failure.
Furthermore, in the latter prior art example, there are limits on the diameter of the electrical wires that can be used. Moreover, there is a danger that the tip ends of the insulator barrel will strike each other and bite into the outer covering of the electrical wire creating the possibility of damage to the outer covering of the electrical wire.
The present invention was devised to solve the above referenced problems. Consequently, the invention provides a compact electrical contact which has a high press-bonding strength while facilitating a broad range of applicable electrical wire diameters.
The electrical contact of the present invention has an electrical contact part, a conductor barrel that is press-bonded to or in frictional engagement with the core wire of an electrical wire, and an insulator barrel that is press-bonded to or in frictional engagement with the insulating covering of the electrical wire. The insulator barrel is constructed from a pair of left and right press-bonding parts disposed in positions that are offset relative to each other in the axial direction of the electrical wire. The electrical contact is constructed so that when the press-bonding parts are press-bonded to the electrical wire, the facing edges of the press-bonding parts, which face each other in the axial direction, contact each other on the electrical wire.
Both surfaces of the facing edges of the press-bonding parts may be subjected to swage working. Alternatively, the entire circumferences of only the inside surfaces of the press-bonding parts may be subjected to swage working. Or the entire circumferences of the outside surfaces may be subjected to swage working in addition to the entire circumferences of the inside surfaces.
The term xe2x80x9cboth surfaces of the facing edgesxe2x80x9d refers to both the inside surfaces of the facing edge parts of the plate members that form the press-bonding parts, i.e., the surfaces that contact the outer covering of the electrical wire when press-bonding is performed, and the outside surfaces of the facing edge parts, i.e., the surfaces that can be seen from the outside following press-bonding.
The term xe2x80x9centire circumferencexe2x80x9d does not necessarily refer strictly to the entire circumference of each press-bonding part; this term also refers to cases in which the area in the vicinity of the fixed end of each press-bonding part is not included in this circumference.
The shapes of the tip end portions of the press-bonding parts and the shapes of the corresponding portions that face these tip end portions during the press-bonding of the press-bonding parts may be complementary shapes. In addition to cases in which the shapes of the entire tip end portions of the press-bonding parts and the shapes of the corresponding portions of the electrical contact are shapes that are complementary to each other, the term xe2x80x9ccomplementaryxe2x80x9d also includes cases in which the shapes of only portions of the tip end portions and the shapes of the corresponding portions are shapes that are complementary to each other.
The electrical wire press-bonding method using the electrical contact of the present invention is also described. When the electrical contact is press-bonded to the electrical wire, the pair of press-bonding parts make sliding contact with each other at the facing edges of said press-bonding parts, so that the respective tip ends of the press-bonding parts move while describing portions of a spiral track along the outer circumference of the aforementioned electrical wire.